BLOOD-GROUP ABO-RELATED GLYCOSYLATION OF UROTHELIAL CELL-LINES - IMMUNOCYTOLOGICAL, ENZYMATIC, AND GENETIC-CHARACTERIZATION

Three immortalized, human urothelial cell lines were characterized wit h respect to their ABO-related carbohydrate phenotypes using a panel o f monoclonal antibodies directed to a series of carbohydrate epitopes (Lac, sialylated Lac, Le(a), sialylated Le(a), Le(x), sialylated Le(x) , H types I and II, Le(y), Le(b), A monofucosylated types I and II, AL e(y), ALe(b), and A type III). The glycosyltransferases forming some o f these epitopes (beta 1-3/4 galactosyltransferase, alpha 1-2 fucosylt ransferase, alpha 1-3 galactosyltransferase, and alpha 1-3-N-acetyl-ga lactosaminyltransferase) were determined by enzyme assays. The ABO gen e complex was analyzed by Southern blotting, Northern blotting, and po lymerase chain reaction across the O deletion and across base differen ces between the A and B alleles. The immunocytochemical stainings show ed marked differences between the three cell lines; the high grade (tu morigenic, metastatic) cell line showed difucosylated types I and II s tructures, and the low grade (nontumorigenic, nonmetastatic) cell line s showed monofucosylated types I and II structures. Polymerase chain r eaction genotyping of the cell lines indicated that one was OO, one wa s AA, and one was A plus a mutated allele. Northern blotting showed RN A encoding the A transferase. However, even though both of the A cell lines seemed to have an intact gene, which could produce A transferase and transcibed RNA, none of them showed any activity of the A gene en coded enzyme or any A-structures at the cell surface. In contrast, the three other examined glycosyltransferases were active. The three urot helial cell lines reflect in vivo findings in humans. They represent a competent system for in vitro studies of the different carbohydrate t ransferase genes responsible for the carbohydrate structures expressed on the cell surface in bladder tumors.